A method for molding a plain cloth in three dimensions is known in the art. For example, U.S. Pat. No. 5,296,182 or 5,389,318 discloses a method of an integral molding carried out by using a reaction of a polyurethane foam which is a typical liquid foamable mixture. In such a method, while a gasification reaction of the liquid foamable mixture is completed so that the liquid foamable mixture is solidified, polyurethane and a plain cloth as a surface material are integrally molded by a pressure in a mold which has an upper portion and a lower portion having predetermined shapes, respectively. After the polyurethane is pressurized and compressed in the mold for a certain period, the pressurized and compressed polyurethane is transformed into a solid body, and as a result, a three dimensional molded body having a desired pattern can be produced.
Such a method for molding in three dimensions in accordance with the art has been widely applied to several techniques for printing in three dimensions to print a pattern on a surface of a surface material such as shirts, jeans, jackets and the like.
However, there are several problems in such a method of the art, as follows.
As a problem, in a method for molding in three dimensions in accordance with the art, polyurethane is used because the cushioning ability is important so that a thickness thereof is required to be large. Thus, such a method of the art which uses polyurethane is not suitable for applying a thin plain cloth, a carpet and the like.
As another problems, polyurethane foam used in the art is not suitable for a mass production, because most of such methods in the art are carried out by a dispensing method, and the productivity is lowered thereby.
As still another problem, when a large three dimensional molded body is produced by polyurethane used in the art, it is necessary to coat uniformly and rapidly a foamed body, which has a rising height with a relatively large thickness (preferably, 20 mm), over a whole of a surface thereof in order to obtain the stiffness. However, it is difficult to coat uniformly and rapidly the urethane foam by the dispensing method in the art. Thus, a rate of the reaction varies locally in the coated urethane foam, so that there are portions where the reaction has not been started and portions where the reaction has been started in the coated urethane foam, and it is almost impossible to accurately take a pressurization-timing thereby. As a result, the shape of the resulting three dimensional molded body is injured (or deformed) and a relationship in contact between the urethane and the surface material is worse.
As still another problem, when a foamed body of a urethane foam used in the art is pressurized and compressed, a surface of a surface material is pushed up by gas retained under a back side of the surface material if gas contained in the foamed body is not completely removed, so that projections can be formed on the surface of the surface material, and as a result the shape thereof is injured.
As still another problem, because it takes a long time to transform a urethane foam used in the art into a solid body, a working operation is strained to stop during the period for this transformation, and the working efficiency is lowered thereby.
Therefore, an object of the present invention is to provide a relatively thin three dimensional molded body, which has an excellent shape-maintainability and can be applied for carpets, bags and the like which do not need the cushioning ability.
Another object of the present invention is to provide a method for manufacturing a three dimensional molded body which has a shape-maintainability and can easily take a pressurization-timing when producing a relatively large three dimensional molded body.
Still another object of the present invention is to provide a method for manufacturing a three dimensional molded body which can improve productivity and can reduce cost for the production.